Electrical trolley cable apparatus



May 16, 1950 B, W, BENBQW 2,508,091

ELECTRICAL TROLLEY CABLE APPARATUS Filed Dec. 26, 1944 INVENTOR. l v Surf/'5 l/V enbon/ A rfc/:NE Y C Patented May 16, 1950 UNITED STATES PATENT OFFICE 4 Claims.

This invention relates generally to electrical trolley cable apparatus of the type suitable for use with various movable appliances such as hoists, cranes, small electrical locomotives, or the like.

In apparatus of the above type it is common practice to utilize extended cable conductors oi suitable size and supported at intervals by suitable insulators. In the majority or" installations the cables are bare and therefore workmen are exposed to the hazards of accidental contact. It has been proposed to protect the conductors against accidental contact by the use of insulating shrouding, with the shrouding formed in such a manner as to permit continuous electrical contact. A shrouded conductor of this type is disclosed for example in my Patent No. 2,255,874. Certain problems are encountered in the construction and installation of such equipment, including particularly the supporting of the conductor without sag and the provision of features to facilitate utilization with traveling trolley or contacting devices.

It is an object oi the present invention to provide a cable conductor assembly of the type having a shroud oi insulating material and which has novel means forming a trackway for a traveling contacter device7 together with means for attaching the assembly to a xed support.

A further object of the invention is to provide apparatus of the above character having novel means for releasably attaching the shrouded cable assembly to convenient xed supports, and which will facilitate installation of the apparatus or the removal of sections for replacement or repair. l

Another object of the invention is to provide novel means for coupling together sections of a shrouded trolley cable assembly.

A further object of the invention is to provide a shrouded cable assembly having threaded connections between conductor sections, together with means whereby these connections are maintained tight at all times.

Further objects of the invention will appeal' from the following description in which the preferred embodiment has been set forth in detail in conjunction with the accompanying drawing.

Referring to the drawing- Fig. 1 is a side elevational View illustrating aping contacting device.

Fig. 2 is an enlarged side elevationalview oi the cable assembly, with a portion of the same in cross section.

Fig. 3 is a cross sectional View taken along the line 3 3 of Figure 2.

Fig. 4 is a detail illustrating one of the gripping devices utilized in the assembly oi Fig. 1.

Fig. 5 shows the same device as Fig. 4, but looking at the reverse side.

Fig. 6 is an enlarged view looking toward the end of Fig. 4, and partly in cross section.

Fig. 7 is a side elevational view illustrating the terminal boxes at the ends of the cable assembly, and means in conjunction with the boxes for applying torsional tension to the cable conductor.

The apparatus illustrated in Fig. 1 consists generally of a cable conductor assembly designated generally at lil, suspended from suitable supporting means by the gripping devices Il, and being utilized in conjunction with a traveling contactor device I2. Device l2 can be of the type disclosed in my Patent No. 2,255,874 granted September 16, 1941.

The assembly I0 preferably includes (Fig. 3) an extended cable conductor I3 made of suitable f material such as hardened copper, and of suitable diameter for the current carrying capacity desired. About the cable conductor I3 there is a shroud Ill formed of suitable insulating material, preferably resilient material such as molded natural or synthetic rubber. While the specic iorm of the shroud may vary, in this instance it includes side portions Illa, and lsb, which are joined below the conductor I3 by the teeth-like bars I6. 1t is desirable that the conductor I3 have a comparatively loose t within the shroud, as distinguished from a bond between the metal and the rubber. This enables insertion or removal of lengths of the conductor from the shroud, after the shroud has been assembled with the backing to be presently described. Between the teeth-like bars I6 there are open recesses or cavities Il, through which the surface of the conductor I3 is accessible for electrical connection.

Attached to the back or upper side of the shroud IG there is a relatively rigid mounting designated generally at It. This mounting is formed in such a manner as to provide the parallel and unobstructed trackways lila and |91), extending longitudinally of the conductor I 3. Intermediate these trackways there is a rib-like portion Isc which stiffens the assembly, and which is utilized for engagement with the gripping devices II.

It is desirable to make the entire mounting I8 from a strip of suitable sheet metal which is bent upon itself to the general T-shaped form shown in Figure 3. After bending the strip to the general form illustrated, the edge portions 2l are iinally crimped over the raised ridges 22 of the shroud, in order to form a secure clamping engagement. It will be noted in this instance that the upper side of the shroud above the conductor I3 is longitudinally slit as indicated at 23 in order toenable introduction of the conductor I3. Because of the clarnpingeffect of crimped edges 2|,"the adjacent 'surfaces along the slit are pressed tightly together.

The doubling of the sheet metal to form the rib portion IQc is such that a relatively narrow longitudinal channel 24 is formed. As ywill be presently explained this channel is desirable inconjunction with the means l'for c ovupling together adjacent sections.

Each of the grippingdevices Il (Figs, 4 to 6) utilize tongues which extend alongside the rib ISC, andthey are 'constructedwhereby a removable locking pin can be inserted to insure .tight clamping engagement. rthus each device is made of a pair of at sheet metal `strips 26 and 2l, having .their .upper .portions suitably secured vtogether and attachedto a suitable mounting member 28. `It will beevidentlthat member 28 can vary to suit dilerent requirements, but `in this instance .it is .in the .form of a pressed metal channel. The .web .of the .channel is slotted to receive theupper ends .of .strips 25 and 2?, and above the web'the strips are bent over as indicated at .29 .and 4welded .or otherwise suitably secured to .the web. The ,lower end of strip 2 terminates along .the lines r3 I, except for an intermediate portion .which is extended to form the tongue 32. .Strip 26is cutaway to accommodate -the tongue 32, Vandit vhas .two lower portions 33 forming spaced .tongues .upon the opposite sides of the .tongue 32. All of these .tongues 3l, 3 2 have .lower inturnededges 34 .to engage at the base of the rib ISc. Immediately above the tongues 31,32 .the strips 2 6, 21 are made slightly concave'as indicated at 35, 31, .to ,form a recess 38 capable of receiving .the locking pin 3,9. B efore the locking pin can .be conveniently inserted the tongues .32, 33. must `be pressed upon {opposite sides .of the. rib. 1,90, after which the locking .pin can be. inserted to retain V.thetongues in gripping engagement with `the sides of the rib.

.When it is desired .to remove a conductor assembly from a particular .device I l it is only necessary toremove the locking pin, after which `the tongues. 3 2. 33 .are permitted t0 Spring Ont..- wardly when one .applies reasonable .downward force upon the assembly Iii. It will benoted that normally tongues 32 and 33 are suicienllly close .together .that when the rib ISc is insertedbetween .the same, there is sufcient retention due to the resilient character of the. tongue .to temporarily support the conductor assembly. This is a desirable feature in that it facilitates making installations. After sections of the assembly I0 have been tempararily suspended in this manner, then the locking vpins can be applied to provide a permanent grip.

It will be evident that in an actual installation the number of assemblies le supported in juxtaposition to each other will depend upon particular requirements. In a typical installation two or three such conductor assemblies are supported side by side from common supporting members 28, and these members in turn are suitably attached to structural members of .the building in which the installation is being made.

In practice it is desirable to make the assembly l0 in sections of standardized lengths, so that for a given installation a sufficient number of these sections will be connected together to form a continuous assembly of the length desired. 2 illustrates a convenient and novel type of coupling means for connecting together adjacent sections. Thus a flat metal strip 4I Kis provided, dimensioned to t within the channel 24. The end portions of this stripare bifurcated or forked, to provide upper and lower branches or legs :4 2, 43 of considerable resiliency. The upper branches 43 have projecting lugs 44 which nor- .mally ocupy slots llt provided in the upper edge `of the rib Ide. The lower branches 43 have rounded corners il to facilitate insertion into the channel 1.2.4-

Thevcoupling member 4I is utilized as follows: One end portion is first inserted into the channel 2 of a section to be connected, by springing the branches d2, 43 together. When it has .been inserted sufficiently far lug .4.4 engages within the slot 4E. Then the .projecting end of member VII :is .inserted in the other section in thesame manner, whereby the two sections nally occupy the .position shown in Fig. 2.

Itis also .desirable to construct ythe cable conductor .i3 in sectionsof convenient standardized lengths. These sections are then .preferably .threaded together as shown in Fig. 2. Thus one .end of Va section can be provided with a male stud threaded for engagement with an in.- ternally threaded opening4Q, provided in the end loi an adjacent conductorsection.

When Va number of such cable Vconductor sec.- .tions are utilized, with threaded engagement be.- ,tween the same, it is important that the `threaded connections be maintained tight. For this pur.- 4pose I provide means whereby `the entire length of cable conductor is maintained under torsional tension. As shown in Fig. 7 the ends of the conductor are associated with the metal terminal boxes 5I, 52, which facilitate .making the neces.- sary ,electrical connections. The cable conductor .projects considerably 1beyond the shroud I4 and .estende through Suitable insulating .block .5.3 into the interior of the adjacent box. A set rscrew 54 is threaded into block 53 to grip and retain the conductor in any desired .angular posi.- tion. Upon completing an assembly setscrew 54 is clamped upon one end of the cable conductor, as for example within the box 5I. In the 4other box the projecting end of the .conductor I3 is turned in a direction to tighten all of the threaded connections, and V.in .order to apply torsional strain to the conductor within its elastic limit. 'I he adjacent set screw 54 is then tightened to hold the entire length of conductor under such torsional tension. The torsional strain is transmitted throughout the length of the conductor because of the fact thatthe conductor is not bonded to the surrounding shroud.

The traveling contacting device I2 is illustrated only generallyfand need not be described in detail. Briey it can consist of a housing 5 6 serving to enclose an articulated or endless chain type of contacting mechanism as disclosed in the'aforesaid Patent 2,255,874. vThe conducting teeth o f this mechanism are adapted to extend into the recesses I'I to make electrical engagement with the cable conductor I3. Straps 51 extend upwardly from the sides of the housing 56. and at their upper ends they carry the tracking wheels 58. These wheels operate upon the parallel 75 tracks I9a, I9b,.and retain the device I2 in proper position for making good electrical contact. Element 59 represents a suitable towing device attached to the box 56, for moving the device from place to place, as for example in conjunction with operation of a hoist. A exible electrical cable 6| includes conductors which complete a circuit to the cable conductor.

It is clear from the foregoing that I have provided an apparatus having great utility for a wide variety of services. Although the shrouding of the conductor is of relatively resilient material, the `conductor and shrouding assembly is adequately supported without placing longitudinal tension upon the conductor and without appreciable sag. The supporting of the assembly l0 by way of the devices H greatly facilitates making initial installations, as well as to facilitate making changes, alterations, or repairs. The method of coupling illustrated in Fig. 2 likewise facilitates installations and changes, and the manner of connecting together the various lengths of the cable conductor makes for adequate current carrying capacity without heating at the points of connection between sections.

I claim:

l. In electrical trolley cable apparatus, an extended cable conductor, a shroud of insulating material disposed about the conductor, a metal backing attached to the insulating material, the metal backing being formed to provide a. pair of spaced parallel trackways extending longitudinally of the conductor and also forming a rib disposed in a plane substantially at right angles to the general plane of the trackways and intermediate the same, the base of the rib being constricted to provide exterior longitudinal recesses, and means forming a supporting `clip for engaging said rib, said clip comprising a plurality of sheet metal tongues adapted to engage upon opposite sides of the rib without obstructing said trackways, and portions of said tongues extending into said recesses.

2. In electrical trolley cable apparatus, an extended cable conductor, a shroud of insulating material disposed about the conductor, the shroud being in at least two lengthwise sections, a metal backing attached to the insulating material and likewise comprising two sections corresponding to the sections of the shroud, said backing being formed to provide a rib extending lengthwise of the conductor and formed hollow to provide an inner tunnel, the tunnel being spaced laterally from both the conductor and the shroud, and means extending within said tunnel for locking adjacent end sections together.

3. In electrical trolley cable apparatus, an extended cable conductor, a shroud of insulating material disposed about the conductor, the shroud being in at least two lengthwise sections, a metal `backing attached to the insulating material and likewise comprising two sections corresponding to the sections of the shroud, said backing being formed to provide an upstanding and substantially nat rib extending lengthwise of the conductor and formed hollow to provide an inner tunnel which is closed on both its longitudinal edges, and means extending within said tunnel for locking adjacent end sections together, said last named means comprising a flat metal strip having forked end portions, and locking lugs on branches of the end portions adapted to engage in slots provided in the ribs.

4. In electrical trolley cable apparatus, an extended cable conductor formed in a plurality of sections, said sections having threaded connections, an insulating shroud surrounding the conductor, means for securing the shroud to a 'fixed support, terminal boxes at the ends of the conductor, and means :at the terminal boxes for clamping the projecting end portions of the conductor and for retaining the entire length of the conductor under torsional tension, the torsional tension being in a direction to retain the threaded connections tight.

BURTIS W. BENBOW.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 453,095 Vinton May 26, 1891 457,105 Boynton Aug. 4, 1891 768,606 Kubierschky Aug. 30, 1904 1,466,893 Dunbar Sept. 4, 1923 1,819,885 Frank Aug. 18, 1931 1,914,467 Stevens June 20, 1933 2,128,135 Glasgow Aug. 23, 1938 2,156,827 Wehr May 2, 1939 2,227,625 Benbow Jan. 7, 1941 2,358,116 Wehr Sept. 12, 1944 

